Function run 

fn run(
    accounts: &[Account],
    password: &dyn Fn(&Account) -> Result<String, SyncError>,
    dirs: &Dirs,
    room: &dyn Fn(&Path) -> Option<u64>,
    progress: &mut dyn FnMut(&Progress),
    cancel: &Cancel,
    download: bool,
) -> Update

update (download), or verify.